In the case of load-carrying transport vehicles, it is common to load or unload a draw-bar type trailer or a semitrailer (articulated trailer), hereinafter referred to as a trailer, by means of a crane mounted on the towing vehicle. If the trailer is of considerable length, the jib of the crane may be too short to reach the rear of the trailer.
In such circumstances loading of the rear part of the trailer has sometimes been carried out by disconnecting the trailer from the towing vehicle and moving the vehicle so that the crane reaches the non-loaded part. This procedure, however, leads to considerable time loss and increased operating costs.